Pulse or digital communications – Receivers – Automatic baseline or threshold adjustment
Patent
1995-05-01
1997-01-28
Chin, Stephen
Pulse or digital communications
Receivers
Automatic baseline or threshold adjustment
315324, 315355, 327 72, 327307, H04L 2506
Patent
active
055984380
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a cordless telecommunication apparatus conversion means for converting an analog RF signal into a digital data stream and having synchronization means for synchronizing the data stream with respect to an apparatus clock, characterized in that the conversion means comprise comparator means which compare the RF signal with a reference signal generated from the former by means of integration and generate the data stream in accordance with the result of the comparison, and in that detection means are provided which, in the case of the first succession of two identical bit values of the synchronized data stream, control the comparator means in such a manner that the integration of the RF signal is interrupted and the integration of the RF signal sections corresponding to the two successive bit values is compensated for.
2. Description of the Related Art
The technical development of communication systems that include cordless telecommunication apparatuses for the cordless transmission of voice and non-voice information is tied to various standards, analogously to the ISDN standard (Integrated Services Digital Network) which has existed for some time in line-connected communications. Apart from some national standards and several cross-boundary standards such as the CT1, CT1+ standard on an analog basis and the CT2, CT3 standard on a digital basis, a standard, the so-called DECT standard (Digital European Cordless Telecommunication; compare European Telecommunication Standard--Final Draft--, prETS 300 175-1 . . . 9, 5/1992, ETS Institute 06921 Sophia Antipolis, France and Philips Telecommunication Review, Vol. 49, No. 3, 9/1991, pages 68 to 73, "DECT, a universal cordless access system" by R. J. Mulder), analogous to the global GSM standard (Group Speciale Mobile or Globals Systems for Mobile Communication; compare Informatik Spektrum Vol. 14, No. 3, 6/1991, pages 137 to 152, "Der GSM--Standard--Grundlade fur digitale europaische Mobilfunknetze") (The GSM Standard--Basis for Digital European Mobile Radio Networks) by A. Mann) for mobile radio, has been created on a European scale for the lower-power cordless communication between portables and a base station, with ranges of some 100s of meters. It is an essential feature of the DECT standard that the base station can be connected to line-connected communication networks (e.g. PSTN=Public Switched Telephone Network; PTN=Private Telecommunication Network).
For cordless communication according to the DECT standard, a dynamic channel selection of approximately 120 available channels is carried out. The 120 channels result from the fact that in the DECT standard, ten frequency bands between 1.8 and 1.9 GHz are used, a time-division multiplex frame of 10 ms being used in time-division multiplex access (TDMA) in each frequency band according to the representation in FIG. 1. In this time-division multiplex frame, 24 time channels (from 0 to 23) are defined, which provide a frame structure. This frame structure is then used in such a manner that for each frequency band, 12 mobile stations MS with a base station BS of a DECT communication system can operate simultaneously in duplex mode (MS-BS and BS-MS or, respectively, BS-MS and MS-BS). A time slot of in each case 417 .mu.s is allocated to the 24 time channels.
This time slot specifies the time in which information (data) are transmitted. This type of transmitting information in duplex mode is also called the ping-pong method because transmission takes place at a particular time and reception takes place at another time. In this ping-pong method, one time frame or pulse (burst) of 365 .mu.s is transmitted in each time slot, which approximately corresponds to a frame length of 420 bits, with a data throughput of 42 kbit/s. Taking into consideration that in each case 30 bits are available in a guard space at both ends of the time frame in order to avoid overlaps by adjoining time slots, this results in a total data throughput of 1,152 MBit/s re
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A. Mann, "DER GSM-Standard--Grundlage fur digitale europaische Mobilfunknetze", Informatik Spektrum, 8350, 14 Jun. 1991, No. 3, pp. 137-152.
R. J. Mulder, "DECT, a universal cordless access system", Philips Telecommunication Review, vol. 49, No. 3, Sep. 1991, pp. 68-73.
Research Disclosure, 2244, No. 309, Jan. 1990, New York(US), S. 18, Normen Nescio "On Chip Clock Receiver Circuit".
Chin Stephen
Nguyen Thuy L.
Siemens Aktiengesellschaft
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